>>22709600Blue, or Gary if you'd prefer.
Thanks to nostalgia.
I remember beating the E4 on Yellow for the first time, my Pokémon were worn out completely and I thought I had become the champion. Then suddenly, nope, another battle.
Fuck I was hyped, of course I got my shit kicked in because I wasn't prepared at all.
I guess the fact that he's been your rival (not just "friend" or "companion" like in the newer games) adds to it.
My opinion is 100% based on nostalgia bias, though.